沿海农村地区大气 PM_(2.5)中多环芳烃(PAHs)季节污染特征、气象条件影响及健康风险评估

Pollution characteristics,impacts of meteorological conditions and health risk assessment of polycyclic aromatic hydrocarbons(PAHs)in atmospheric PM_(2.5) in different seasons in coastal rural areas of China

东部沿海地区是我国多环芳烃排放量最高的地区之一,了解我国东部沿海农村地区大气多环芳烃(PAHs)污染特征和健康风险是大气污染控制的重要基础之一.在本研究中,对青岛农村地区进行了春、夏、秋、冬季的大气PM_(2.5)样品采集,并对其18种PAHs的季节变化、分子组成和与气象要素关系进行了分析,利用总致癌当量毒性(∑TEQ)模型对PAHs进行了健康风险评估.PM_(2.5)浓度季节变化趋势与PAHs浓度季节变化趋势具有一致性,变化趋势为:冬季>秋季>春季>夏季,PM_(2.5)年均浓度为(33.91±28.96)μg·m^(-3),PAHs年均浓度为(11.66±20.00)ng·m^(-3).PAHs(除BkF外)与相应期间内的PM_(2.5)、PM_(10)、SO_(2)、NO_(2)、CO和气压呈正相关性(p<0.01),但是与O_(3)、气温呈负相关性(p<0.01).通过诊断比率计算,表明煤燃烧和机动车排放是农村地区PAHs的重要来源.冬季大气PM_(2.5)中PAHs的总致癌当量毒性(ΣTEQ)超过WHO限值(TEQ 1 ng·m^(-3)),对人类具有明显危害,应对沿海农村地区冬季PAHs的污染给予重视.

The eastern coastal region of China is the area with the highest emission of PAHs in China.Understanding the pollution characteristics and health risk of polycyclic aromatic hydrocarbons(PAHs)is one of important basis for air pollution control in eastern coastal rural area of China.In this study,we collected PM_(2.5) samples in spring,summer,autumn and winter in rural areas of Qingdao.The seasonal variation,molecular composition and relationship with meteorological elements of 18 PAHs were analyzed,and the total carcinogenic equivalent toxicity(ΣTEQ)model was used for PAHs health risk assessment.We found that the seasonal variation trend of PM_(2.5) concentration was consistent with that of PAHs concentration.The variation trend was:winter>autumn>spring>summer.The average annual concentration of PM_(2.5) was(33.91±28.96)μg·m^(-3),and the average annual concentration of PAHs was(11.66±20.00)ng·m^(-3).PAHs(excluding BkF)were positively correlated with PM_(2.5),PM_(1.0),SO_(2),NO_(2),CO and air pressure in the corresponding period(p<0.01),but negatively correlated with O_(3) and air temperature(p<0.01).The diagnostic ratio analysis showed that coal combustion and vehicle emission were important sources of PAHs in rural areas.The total carcinogenic equivalent toxicity(∑TEQ)of PAHs in winter exceeded the limit set by the WHO(TEQ 1 ng·m^(-3)),which was extremely harmful to humans.Our study showed that attention should be paid to the pollution of PAHs in coastal rural areas in winter.